MilliporeSigma
  • Home
  • Search Results
  • Mitochondrial damage contributes to Pseudomonas aeruginosa activation of the inflammasome and is downregulated by autophagy.

Mitochondrial damage contributes to Pseudomonas aeruginosa activation of the inflammasome and is downregulated by autophagy.

Autophagy (2015-02-24)
Majid Sakhi Jabir, Lee Hopkins, Neil D Ritchie, Ihsan Ullah, Hannah K Bayes, Dong Li, Panagiotis Tourlomousis, Alison Lupton, Daniel Puleston, Anna Katharina Simon, Clare Bryant, Thomas J Evans
ABSTRACT

The nucleotide-binding domain, leucine-rich repeat containing family caspase recruitment domain containing 4 (NLRC4) inflammasome can be activated by pathogenic bacteria via products translocated through the microbial type III secretion apparatus (T3SS). Recent work has shown that activation of the NLRP3 inflammasome is downregulated by autophagy, but the influence of autophagy on NLRC4 activation is unclear. We set out to determine how autophagy might influence this process, using the bacterium Pseudomonas aeruginosa, which activates the NLRC4 inflammasome via its T3SS. Infection resulted in T3SS-dependent mitochondrial damage with increased production of reactive oxygen intermediates and release of mitochondrial DNA. Inhibiting mitochondrial reactive oxygen release or degrading intracellular mitochondrial DNA abrogated NLRC4 inflammasome activation. Moreover, macrophages lacking mitochondria failed to activate NLRC4 following infection. Removal of damaged mitochondria by autophagy significantly attenuated NLRC4 inflammasome activation. Mitochondrial DNA bound specifically to NLRC4 immunoprecipitates and transfection of mitochondrial DNA directly activated the NLRC4 inflammasome; oxidation of the DNA enhanced this effect. Manipulation of autophagy altered the degree of inflammasome activation and inflammation in an in vivo model of P. aeruginosa infection. Our results reveal a novel mechanism contributing to NLRC4 activation by P. aeruginosa via mitochondrial damage and release of mitochondrial DNA triggered by the bacterial T3SS that is downregulated by autophagy.

MATERIALS
Product Number
Brand
Product Description

Resveratrol, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Potassium phosphate monobasic, meets analytical specification of Ph. Eur., NF, E340, anhydrous, 98-100.5% (calc. to the dried substance)
Sigma-Aldrich
Potassium phosphate monobasic, ACS reagent, ≥99.0%
Sigma-Aldrich
Potassium phosphate monobasic, buffer substance, anhydrous, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., 99.5-100.5%
Supelco
Rapamycin, VETRANAL®, analytical standard
Supelco
L-Glutamine, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Glutamine
Sigma-Aldrich
Anti-BrdU antibody, Mouse monoclonal, clone BU-33, purified from hybridoma cell culture
Supelco
Sucrose, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Resveratrol, certified reference material, TraceCERT®
Supelco
N-Acetyl-L-cysteine, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Monobasic potassium phosphate, United States Pharmacopeia (USP) Reference Standard
USP
Sucrose, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Potassium phosphate monobasic, powder, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99.0%
Sigma-Aldrich
Sucrose, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥99.5% (GC)
Sigma-Aldrich
Sucrose, Grade I, suitable for plant cell culture
Sigma-Aldrich
Sucrose, Grade II, suitable for plant cell culture
Sigma-Aldrich
Sucrose, meets USP testing specifications
Supelco
L-Glutamine, certified reference material, TraceCERT®
Sucrose, European Pharmacopoeia (EP) Reference Standard
Supelco
Monobasic Potassium Phosphate, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Ethylenediaminetetraacetic acid, purified grade, ≥98.5%, powder
Sigma-Aldrich
Ethylenediaminetetraacetic acid, anhydrous, crystalline, BioReagent, suitable for cell culture
Sigma-Aldrich
N-Acetyl-L-cysteine, BioReagent, suitable for cell culture
Sigma-Aldrich
Ethylenediaminetetraacetic acid, ACS reagent, 99.4-100.6%, powder
Sigma-Aldrich
N-Acetyl-L-cysteine, BioXtra, ≥99% (TLC)
Sigma-Aldrich
Ethylenediaminetetraacetic acid, BioUltra, anhydrous, ≥99% (titration)
Sigma-Aldrich
Sucrose, ≥99.5%
Sigma-Aldrich
Sucrose, ACS reagent
Supelco
Sucrose, analytical standard, for enzymatic assay kit SCA20